"Evidence is growing that employees are instructed to report on their encounters with South Korean citizens and use these sites as intelligence gathering proxies," it writes. For example: "In Nepal in September 2011, authorities raided a North Korean restaurant named Okryugwan on suspicions of tax evasion. Confiscated materials, however, included suspicious documents including dialogues of customers and personal information of South Korean guests, such as the names of patrons and when they entered."

The ethics of dining at the restaurants can be complicated. As TheSpec.com has reported about the Pyongyang Restaurant in Amsterdam:

"While challenging perceptions of North Korea, the restaurants raise a tangle of questions about how the world should interact with the country and its reclusive government, accused of human rights abuses and a rogue nuclear weapons program. ...

"There is no way of knowing whether the Pyongyang government benefits from the Amsterdam restaurant financially, but Marcus Noland, a North Korea expert who has written five books on the country, said the main purpose of such restaurants is to get around international economic sanctions and obtain foreign money with no strings attached."

Quite a few patrons seem to have enjoyed dining at the establishments, judging from the number of YouTube videos we see showing the waitresses and entertainers. Here's one from Bangladesh.

This whole thing about spying waitresses has an old blogger thinking about Warren Zevon's Lawyers, Guns and Money:

Well, I went home with the waitressThe way I always doHow was I to knowShe was with the Russians, too